The vertical stanchions which maintain the spacing of the two outer rings, are not rigidly connected with these rings. The rings and stanchions are flexibly linked using INA Elges spherical plain bearings GE..-UK.

Since these bearings allow motion in all directions, they permit the adjustment required by the cable system of the roof.

If the rings and vertical stanchions were rigidly linked, this would transmit moments into the roof construction. INA Elges spherical plain bearings GE..-UK were therefore selected.

The ends of the vertical stanchions are of a double section design, while the mounting flanges on the outer rings have a single section design.

The seatings of the mounting bolts are protected by covers.

The spherical plain bearings have contact seals on both sides to prevent the ingress of contamination.

Larger bearings were required directly above the vee stays. The cables which tension the inner ring to its correct shape are fixed at these node points. A larger force is required at these points.

The INA Elges spherical plain bearings have a sliding contact surface comprising hard chromium plated steel and PTFE fabric.

The inner ring is hardened and the slideway for the PTFE fabric has a hard chromium plating. The PTFE fabric is supported in the split outer ring of the bearing.

Due to this design, the spherical plain bearings are maintenance-free. This is an important feature of the roof construction.